1. Field of the Invention
This invention relates to a switch device including an operating plate which is pushed or otherwise operated so that a switching means is switched from one state to another.
2. Description of the Prior Art
FIGS. 10 and 11 illustrate one of conventional switch devices of the above-described type. The shown switch device comprises a generally rectangular operating plate 1, a base 2 and two coil springs 3. Each spring 3 has both ends connected to the operating plate 1 and the base 2 respectively. A push-button switch 4 is provided on the base 2 so as to correspond to a central portion of the operating plate 1. When the operating plate 1 is pushed, an operating element 4a of the push-button switch 4 is depressed as shown in FIG. 11 so that the switch is switched from an OFF state to an ON state, for example.
In the aforesaid switch device, however, the operating element 4a of the push-button switch 4 is depressed directly by the backside of the operating plate 1. Accordingly, when the central portion of the operating plate 1 is pushed, a distance of movement of a portion of the operating plate abutting against the operating element 4a is larger than one when a peripheral portion of the plate 1 away from the central portion is pushed. As a result, the switching operation of the push-button switch 4 becomes unreliable when the peripheral portion of the plate 1 away from the central portion is pushed.
Therefore, an object of the present invention is to provide a switch device in which the operating plate has a broader operable range.
The present invention provides a switch device comprising a base, an operating plate disposed opposite the base and including an outer face that may be depressed at any part thereof so that the operating plate is displaced from a neutral position to a proximity position where the operating plate is in proximity to the base, a first movable member provided between the base and the operating plate and having a first pivot shaft which extends along the operating plate and about which the first movable member is caused to pivot when the operating plate is depressed, a second movable member provided between the base and the operating plate and having a second pivot shaft spaced from and extending in parallel with the first pivot shaft, the first movable member pivoting about the first pivot shaft when a predetermined part of the outer face of the operating plate is depressed, the second movable member pivoting about the second pivot shaft when a part of the outer face of the operating plate other than the predetermined part is depressed, the first movable member pivoting upon pivot of the second movable member, a switching element provided on the base, and a switch operating section provided on the first movable member for switching a state of the switching element when the first movable member pivots.
According to the above-described construction, the switching element is switched by the switch operating section provided on the first movable member pivoting with depression of the operating plate. Consequently, the state of the switching element can reliably be switched regardless of a location of depression of the operating plate. Moreover, the first movable member pivots upon pivot of the second movable member. Accordingly, the first movable member can pivot even when the depression of the operating plate causes only the second movable member to pivot. As a result, an operable range of the operating plate can be broadened.
The operating plate preferably has an outer surface which is depressed, and the operating plate is displaced from the neutral position to the proximity position when any part of the outer surface of the operating plate is depressed.
The operating plate is preferably displaced from the neutral position to a distant position spaced away from the base when drawn, so that at least one of the first and second movable members is caused to pivot. The operability of the switch device can be improved since the switching element is switched when the operating plate is either depressed or drawn. In this construction, the operating plate preferably includes at least one operating plate shaft parallel with each of the first and second pivot shafts, the operating plate pivoting about one of the operating plate shafts.
The operating plate preferably includes a hand hold formed on one end thereof at the operating plate shaft side, the hand hold being drawn so that the operating plate is caused to pivot about the operating plate shaft to be displaced from the neutral position to the distant position. Further, the operating plate preferably has a pivot thereof transferred sequentially from the operating plate shaft located away from the hand hold to the operating plate shaft located near the hand hold as the operating plate is displaced from the neutral position to the distant position.
On the other hand, FIG. 4 shows a case where a lower part of a front or outer surface of the operating plate 29 assuming the neutral position is depressed in the direction of arrow C. In this case, the operating plate 29 is caused to pivot about the engaged portion of the engaging and engaged members 32 and 49 in the direction of arrow C until the backside of the plate 29 abuts against the stopper 54, whereupon the operating plate is displaced to assume a proximity position where it is in proximity to the unit base 23 or the auxiliary base 48. As a result the projection 45 abut against the second operating portions 53 respectively such that the second movable member 42 is caused to pivot about the shafts 43 against the urging force of the torsion coil spring 46 in the direction of arrow D in FIG. 4 or opposite to arrow A. The projection 44 of the second movable member 42 is then spaced from the receiving portion 41 such that the first movable 37 assumes a free state. As a result, the operating element 27a projects forward so that the push-button switch 27 is switched to the ON state. Further, the switch operating section 40 is pushed upward as the result of projection of the operating element 27a, whereupon the first movable member 37 is caused to pivot in the direction of arrow E or opposite arrow B.
In the above-described construction, a distance between the pivot and the hand hold is long at an initial stage of the drawing of the operating plate and short at a last stage of the drawing. Accordingly, the operating plate can start to pivot by application of a small force to the hand hold. Furthermore, a moment acting on the operating plate shaft serving as the pivot of the operating plate can be rendered small even when a large force is applied to the hand hold at the last stage of the drawing. Consequently, the breakage of the operating plate shaft can be prevented.
The switch device preferably further comprises a pair of first operating portions provided on portions of the base corresponding to both ends of the operating plate with respect to one direction, the first operating portions causing the first movable member to pivot when the operating plate is depressed, and a pair of second operating portions provided on portions of the base corresponding to both ends of the operating plate with respect to one direction, the second operating portions causing the second movable member to pivot when the operating plate is depressed. The first movable member can reliably be caused to pivot even when a peripheral end portion of the operating plate is depressed.
While the operating plate is assuming the neutral position, the first movable member is preferably spaced away from the first operating portion and the second movable member is spaced away from the second operating portion. Even when parts of the switch device have respective dimensional errors, the first and second operating portions can be prevented from causing the first and second movable members to pivot while the operating plate is assuming the neutral position.
The switching element preferably comprises a push-button switch having an operating element depressed by the switch operating section while the operating plate is assuming the neutral position. The operating element is released from the depression by the switch operating section when the operating plate is operated. That is, the operating element can be prevented from being broken since it is not subjected to a large shock during operation of the operating plate.